Blood Urea Nitrogen to Creatinine Ratio and Long-Term Mortality in Patients with Acute Heart Failure: A Prospective Cohort Study and Meta-Analysis

Objective: To further explore the relationship between the blood urea nitrogen to creatinine (BUN/Cr) ratio and the prognosis of patients with acute heart failure (AHF), a two-part study consisting of a prospective cohort study and meta-analysis were conducted. Methods: A total of 509 hospitalized patients with AHF were enrolled and followed up. Cox proportional hazards regression was used to analyze the relationship between the BUN/Cr ratio and the long-term prognosis of patients with AHF. Meta-analysis was also conducted regarding the topic by searching PubMed and Embase for relevant studies published up to October 2019. Results: During a median follow-up of 2.8 years, 197 (42.6%) deaths occurred. The cumulative survival rate of patients with a BUN/Cr ratio in the bottom quartile was significantly lower than in the other 3 groups (log-rank test: p = 0.003). In multivariate Cox regression models, the mortality rate of AHF patients with a BUN/Cr ratio in the bottom quartile was significantly higher than in the top quartile (adjusted HR 1.52; 95% CI 1.03-2.24). For the meta-analysis, we included 8 studies with 4,700 patients, consisting of 7 studies from the database and our cohort study. The pooled analysis showed that the highest BUN/Cr ratio category was associated with an 77% higher all-cause mortality than the lowest category (pooled HR 1.77; 95% CI 1.52-2.07). Conclusions: Elevated BUN/Cr ratio is associated with poor prognosis in patients with AFH and is an independent predictor of all-cause mortality.